U.S. Naval Institute Naval History & Heritage Command

On July 11, 1942, U.S. military personnel inspect a Japanese Zero aircraft piloted by Tadayoshi Koga that crashed on Akutan Island after bombing Dutch Harbor on June 4, 1942. The Zero was later shipped to the US and put into flying condition for intelligence purposes. Koga was killed in the crash. Photo by Navy Photographer’s Mate Arthur W. Bauman

From Naval History and Heritage Command, Communications and Outreach Division

Some called it the finest fighter in the world, quick, agile with fluid maneuverability. The biggest problem was it wasn’t an American fighter.

The Mitsubishi A6M2 carrier fighter ZERO had long dominated the skies at the beginning of World War II, earning a 12-1 kill ratio against slower, heavier Allied planes.

But American ingenuity and a chance mistake by a ZERO pilot leveled the aerial battleground and gave American pilots a fighting chance.

“In warfare, knowing the capabilities of one’s enemy translates into success on the battlefield and such was the case with intelligence gleaned from the Japanese Zero found in the Aleutians in 1942,” said Hill Goodspeed, historian and artifact collections manager at the National Naval Aviation Museum, Pensacola, Fla. “It was salvaged and restored to flying condition, allowing test pilots to unlock mysteries of the acclaimed fighter’s performance to the benefit of those fighting in the skies over the Pacific.”

Seemed Like a Good Idea at the Time

There was a heavily overcast sky on June 3, 1942 at Dutch Harbor, an American Army and Navy base on Amaknak Island in the Aleutians. When the clouds broke, though, it wasn’t sunshine that burst through – it was a squadron of Kate bombers and ZERO fighters from the carriers Junyo and Ryujo.

The surprise, however, wasn’t for the personnel of Dutch Harbor – an enemy message three weeks earlier had been intercepted and the base had been on high alert waiting for the attack. It was determined the Japanese attack at Dutch Harbor would split the U.S. Navy fleet headed toward Midway. And we all know how that turned out for the Imperial Navy.

As the Japanese pilots flew above the harbor, it was empty of their hoped-for objective: Navy ships. Greeting the incoming fighters instead was a hail of anti-aircraft fire.

Without their main target, the pilots unleased their bombs over Margaret Bay Naval barracks, and strafed the harbor before returning to their ships. They returned the following day to inflict more damage, killing 78 personnel with the loss of 14 aircraft. Of the 40 ZERO fighters involved over the two days, eight aircraft failed to return, with 10 pilots killed and five captured.

One of those dead was Petty Officer 1st Class Tadayoshi Koga in ZERO 4593. He was thought to be among a trio of fighters that downed a Catalina amphibian and then strafed the 7-member crew in their rubber raft until all were dead.

The three ZEROS joined eight others in shooting up Dutch Harbor again, but that was where karma caught up with Koga. Struck by ground fire, the ZERO began trailing oil.

Koga headed for Akutan Island, about 25 miles east of Dutch Harbor and a planned rendezvous spot for stricken fighters as a submarine waited to pick up any downed pilots. Koga prepared to land on what he thought was a grassy flat, but with his landing gear down already, he noticed too late it was actually a marsh.

As the landing gear struck mud, muck and marsh grasses, the plane flipped upside down, killing the 19-year-old Koga. Two other pilots that followed Koga had been given orders to destroy any ZEROS that crash-landed, but unsure whether Koga had survived, they left the plane, hoping he would turn up in the waiting submarine. The sub was soon chased off by the destroyer USS Williamson, but for Koga, who likely died instantly, it mattered little.

Out of sight from ships, and not on a typical path for patrolling planes due to low visibility, the wrecked ZERO could have remained undetected for weeks or months.

It was a serendipitous moment that led to the ZERO’s discovery more than a month later on July 10, 1942. In the days before GPS and radar, pilot Lt. William Thies was patrolling in his PBY Catalina by the use of dead (deduced) reckoning, and got a bit lost. As he reoriented his plane upon sighting the familiar Shumagin Islands and headed back on the most direct course to Dutch Harbor, the wreck was spotted. They marked the coordinates and a salvage team returned the following day. Koga’s body was cut from his harness and buried nearby. But attempts to pull the plane out of the marsh were not as successful. After the third visit on July 15, the ZERO was loaded on a barge back to Dutch Harbor, where it was turned right-side up and cleaned.

Arriving at Naval Air Station North Island near San Diego, the ZERO underwent repairs and its red roundel was replaced with the American blue circle-white star insignia. The plane was fit to fly on Sept. 20 and underwent 24 test flights by Lt. Cmdr. Eddie R. Sanders over the next month.

Navy Lt. Cmdr. Eddie Sanders taxis a captured Imperial Japanese Navy Zero fighter at Naval Air Station San Diego, Calif., in September 1942.

The data received from the plane proved invaluable. The intelligence gained from the find chipped away at Japan’s superiority in the sky. Quick, agile and swift, the ZERO had its Achilles heel: It was sluggish in rolling maneuvers on its right side at speeds higher than 200 knots as gas in its float-type carburetor failed to keep up with gravity. An American pilot in his turbo-charged jet-fueled fighter could escape a pressing ZERO with a diving roll and a hard right at about 200 knots.

In the meantime, then-Lt. Bill Leonard, who was the fighter training officer with Commander Fleet Air, West Coast, had heard about the recovered ZERO despite its top secret status. Leonard and his boss, then-Lt. Cmdr. James Flatley (who retired as a vice admiral), argued the ZERO should be used against fleet units in advanced stages of training just prior to deployment. Based on their information, adjustments were made in new fighters, the F4U Corsair and F6F Hellcat, which gave Navy pilots better performance and superior speed.

The intelligence gained from ZERO 4593, coupled with Lt. Cmdr. John S. “Jimmy” Thach’s “beam defense maneuver” also known as the “Thach Weave,” had more and more Japanese pilots failing in their missions against American and Allied pilots or turning into single-use kamikaze bombers. By the time the last of four Japanese aircraft carriers sank after the Battle of Midway with its aircraft and the experienced pilots who flew them, Japan simply could not replenish its supply with the skill it had at the beginning of the war. Emboldened by success against the once-feared ZERO, American naval pilots turned the tide against the Imperial Navy.

Back on the home front, the idea of using “dissimilar” fighters for dogfight training became a weekday event from 8 a.m. until noon over Manteo, N.C. Pilots in training flew against “adversaries” that included fighters, dive-bombers, torpedo bombers and patrol planes. It provided the best real-time flying experience for young pilots, but was also the most fun, according to then-Cmdr. Tom Blackburn, commanding officer of the Jolly Rogers (VF-17).

It wasn’t until a dogfight between an Army Air Forces P-51 that descended below 500 feet over Norfolk that got Blackburn an uncomfortable conversation about the antics of his “hellions” with Vice Adm. Patrick N.L. Bellinger, commander Air Force, Atlantic Fleet.

Throughout the vast aerial battlefields of World War II, the tactics that proved successful were those evolved from the dissimilar air combat arena – training their own fighters against their enemy’s aircraft. Both Allied and Axis air forces developed specialized units to provide dissimilar air combat training after capturing sufficient examples of their opponent’s aircraft.

Ironically, the most agile fighter in the sky met its fate on the ground in February 1945. The driver of a SB2C Helldiver didn’t see the smaller fighter as it was taxing for take-off at San Diego Naval Air Station and its propeller tore it into scrap. Luickly, the pilot, Cmdr. Richard G. Crommelin, survived the mishap.

Part of the ZEROs wing after a taxi accident destroyed the fighter in Feb. 1945. It is part of a display in the World War II section of the National Museum of the United States Navy in Washington, D.C.

Pieces of the plane were salvaged by Rear Adm. William Leonard and donated them to the National Museum of the United States Navy at the Washington Navy Yard, where they are on display in the World War II section of the museum.

The instrument panel was one of the few things salvaged from a ZERO fighter after it was struck by a larger fighter during a taxi accident in Feb. 1945

“The captured Zero was a treasure,” Rear Adm. William Leonard told American author Jim Reardon for his book Koga’s Fighter: The Fighter that Changed World War II. “To my knowledge no other captured machine has ever unlocked so many secrets at a time when the need was so great.”